Xcode Error: Finder information, or similar detritus not allowed

I haven’t updated my apps lately and I thought I’d see how much work it would be to update to Xcode 8. Well, there is a lot of deprecated code in my apps, since I am still compatible with iOS 5.1.1. I fixed the easy ones but there are still 48 issues left. However, the apps won’t compile now because of this error:
Finder information, or similar detritus not allowed

The error message indicated that the file in question is:

But that is a package, so the problem must be in a file somewhere in there.

Fortunately, this is an error that others have encountered and there is a solution.

First cd to the above named directory and run the following code to find all of the files in the director that have extended attributes.
ls -al@ *

When I ran it I had a bunch of files that have an @ at the end file permissions section. In my case they are all images—in fact all of them are app icon or launch images. My other images are fine.

-rw-r--r--@ 1 username  staff   153369 Jan 12  2013 AppName LaunchImage-Landscape~ipad.png
  com.flyingmeat.Acorn.lastScale        8
        com.flyingmeat.Acorn.selectedLayerId       36
-rw-r--r--@ 1 username  staff    11122 Mar  9  2013 AppName AppIcon72x72@2x~ipad.png
  com.apple.FinderInfo       32
  com.apple.quarantine       60
-rw-r--r--@ 1 username  staff     3958 Sep  4  2013 ShowMe AppIcon40x40@2x.png
  com.apple.metadata:kMDItemWhereFroms      169

The files for this project are all in the Words directory so I recursively removed the attributes from all of the files. Thanks to cwd at StackOverflow for the info on how to do it. I have tens of thousands of files, so it took a while.

xattr -rc /Words